Partially-automated or monitored driving systems are designed to assist drivers in operating a vehicle safely and efficiently on the road, for example, using techniques such as eye-tracking of the driver to send a warning when the driver becomes inattentive, lane tracking of the vehicle to send a warning to the driver when the vehicle is leaving its lane and controlling vehicle velocity based on distance to a vehicle ahead of the driver when adaptive cruise control is activated by the driver. Fully automated driving systems are designed to operate a vehicle on the road without driver interaction or other external control, for example, self-driving vehicles.
Many GPS positioning based vehicle navigation systems rely on the pre-knowledge of the driver's final destination or a driver chosen route to predict the path the vehicle will likely take through a road junction in a roadway where multiple lanes of the roadway split at the junction into two or more sub-paths each containing one or more lanes. Other GPS position based navigation systems use the GPS position of the vehicle to predict the lane in which the vehicle is traveling to predict a path through a road junction. Other systems use a probabilistic approach using different weights for the functional class of the road, the road name, etc., to predict a vehicle's path through road junctions.
Most probable path prediction is a valuable feature as it can be used in vehicle navigation, or to alert the driver before the vehicle enters the road junction, of road characteristics in one of the sub-paths after the road junction.
In automated vehicle driving systems, advance notice of road conditions after a road junction along the most probable path that the vehicle may take through the junction becomes important if the road surface or surface features, such as lane markers, etc., become unavailable in one of the junction sub-paths thereby requiring the driver to retake control of the vehicle. Advance notice of such potential loss of road identification features that could lead to vehicle control loss is important for vehicle operation.